Microsoft has been awarded a patent for using human skin as a power conduit and data bus.
Patent No. 6,754,472, which was published Tuesday, describes a method for transmitting power and data to devices worn on the body and for communication of data between those devices.

In its filing, Microsoft cites the proliferation of wearable electronic devices, such as wristwatches, pagers, PDAs (worn on people's belts) and small displays that can now be mounted on headgear.

"As a result of carrying multiple portable electronic devices, there is often a significant amount of redundancy in terms of input/output devices included in the portable devices used by a single person," says the filing. "For example, a watch, pager, PDA and radio may all include a speaker."

To reduce the redundancy of input/output devices, Microsoft's patent proposes a personal area network that allows a single data input or output device to be used by multiple portable devices.

Personal area networks, or PANs, are nothing new. Some, such as Bluetooth, use radio signals, while others use infrared. Some work has been done on near-field intrabody communications--most notably by IBM's Almaden Research Labs, which at Comdex 1996 demonstrated a prototype device, which was about the size of a pack of playing cards, that let two people exchange electronic business cards by shaking hands.

In its filing, Microsoft says its work addresses wearable devices that are too small to have any kind of interface or even a battery, such as earrings. The company proposes using pulsed AC or DC signals to power the devices. A 100Hz signal could be used to power one device, while a 150Hz signal could be used to power another, the company said, and data signals can be modulated on top of these power signals.

Furthermore, Microsoft said, the physical resistance offered by the human body could be used to create a virtual keyboard on a patch of skin. And just to make sure it has covered all its bases, the filing concludes with a reference for Fido.

"It will be apparent," it says, "that the body may be that of a wide variety of living animals and need not be limited to being a body of a human being."

The new patent is just one of many for the software giant. Since last year, Microsoft has been on a campaign to generate more money from its intellectual property, and in recent weeks the company has obtained patents for double-clicking, XML-scripting methods and a system for generating a to-do list from source code.